- 1.Kingdom of Saudi Arabia Saline Water Conversion Corporation
General Directorate Of Training Programs Training Center JUBAIL
S.MARIMUTHU. GEN.MECHANICAL TECHNICIAN. SWCC. YANBU PLANT ID.402667
MAINTENANCE DEPARTMENT ME C H A N I C A L A D V A N C E D C O U R S
E MACHINEALIGHNMENT " Course Code:23209 Version 1.0 Prepared by:
Fawaz Alghamdi Date:J AN 2005
2. SWCC TRAINING CENTER AL-JUBAIL MECHANICAL MAINTENANCE COURSE
MACHINERY ALIGNMENT LESSON No. 1. SUBJECT/TOPIC : MISALIGNMENTAND
ALIGNMENT TIME : hours OBJECTIVE : At the end of this lesson the
trainee will be able to demonstrate and understanding of
Misalignment and Alignment. LOCATION : Al-Jubail Training Center
TRAINING AIDS : Overhead projector, transparencies, white board.
REF.MANUALS : NUS Training Manual HAND-OUTS : Trainees Manual
LESSON OUTLINE : 1. Introduction. 2. Identifying Misalignment. 3.
Shaft Alignment using a Straight Edge. 4. Wedge Gauge. 3. SWCC
TRAINING CENTER AL-JUBAIL MECHANICAL MAINTENANCE COURSE MACHINERY
ALIGNMENT LESSON No. 2. SUBJECT/TOPIC : HEAT AND ITS EFFECT ON
ALIGNMENT TIME : hours OBJECTIVE : At the end of this lesson the
trainee will be able to describe the effect of Heat on Alignment
without error. LOCATION : Al-Jubail Training Center TRAINING AIDS :
Overhead projector, transparencies, chalkboard, chalk. REF.MANUALS
: NUS Training Manual HAND-OUTS : Trainees Manual LESSON OUTLINE :
1. Introduction. 6. Dowel Pins. 2. Preparations. 7. Aligning Belt
Driven Machinery. 3. Run-Out. 8. Tension Setting. 4. Correcting
vertical Misalignment. 9. End Float. 5. Correcting Horizontal
Misalignment. 4. SWCC TRAINING CENTER AL-JUBAIL MECHANICAL
MAINTENANCE COURSE MACHINERY ALIGNMENT LESSON No.3. SUBJECT/TOPIC :
ALIGNMENT BY RIM AND FACE METHOD TIME : hours OBJECTIVE : At the
end of this lesson the trainee will be able to provdes information
in simple way to accomplish the alignment . LOCATION : Al-Jubail
Training Center TRAINING AIDS : Overhead projector, transparencies,
White board, Marker. REF.MANUALS : NUS Training Manual HAND-OUTS :
Trainees Manual LESSON OUTLINE : Detailed procedure by calculation
and graph 5. SWCC TRAINING CENTER AL-JUBAIL MECHANICAL MAINTENANCE
COURSE MACHINERY ALIGNMENT LESSON No.4 SUBJECT/TOPIC : REVERSE
INDICATOR METHOD. TIME : hours OBJECTIVE : At the end of this
lesson the trainee will be able to provides information in simple
way to accomplish the alignment by reverse indicator method both by
forula and graph. LOCATION : Al-Jubail Training Center TRAINING
AIDS : Overhead projector, transparencies, White board, Marker.
REF.MANUALS : NUS Training Manual HAND-OUTS : Trainees Manual
LESSON OUTLINE : 1- Introduction . 2- Procedure applied 3- Formula
and graph detailed procedure 6. SWCC TRAINING CENTER AL-JUBAIL
MECHANICAL MAINTENANCE COURSE MACHINERY ALIGNMENT LESSON No. 5
SUBJECT/TOPIC : REVERSE MISALIGNMENT METHOD WITH THERMAL GROWTH
ALLOWANCES AND TEMPERATURE GROWTH FACTORS. TIME : hours OBJECTIVE :
At the end of this lesson the trainee will be able to Perform
Alignment by reverse indicator method taking into account different
thermal position or growth factor calculation . LOCATION :
Al-Jubail Training Center TRAINING AIDS : Overhead projector,
transparencies, White board REF.MANUALS : NUS Training Manual
HAND-OUTS : Trainees Manual LESSON OUTLINE : 1. Reverse Alignment
method. 2. Calculating the adjustments. 3. Aligment language and
symbols. 4. Alignment movements. 7. SWCC TRAINING CENTER AL-JUBAIL
MECHANICAL MAINTENANCE COURSE MACHINERY ALIGNMENT LESSON No. 6.
SUBJECT/TOPIC : VERTICAL PUMPALIGNMENT TIME : hours OBJECTIVE : At
the end of this lesson the trainee will be able to understand the
basic concept and procedure of vertical pump alignment. LOCATION :
Al-Jubail Training Center TRAINING AIDS : Overhead projector,
transparencies, Whiteboard,. REF.MANUALS : NUS Training Manual
HAND-OUTS : Trainees Manual LESSON OUTLINE : 1. Important fundament
points for vertical alignment. 8. SWCC TRAINING CENTER AL-JUBAIL
MACHINE ALIGNMENT MODULE HOURS LES SUBJECT/TOPIC No THEORY PRACT
TOTAL HOURS HOURS HOURS ALIGNMENT BASICS PART 1 a. Introduction 1.
b. Identifying misalignment c. Shaft alignment using straight edge
d. Wedge gauge 5 5 10 ALIGNMENT BASICS PART2 a. Misalignment. b.
Factor affecting 2. c. Alignment Tolerance d. Misalignment
Detection e. Types of Alignment f. Alignment Record. 5 5 10 3.
ALIGNMENT BY RIM AND FACE METHOD 5 5 10 REVERSE INDICATOR METHOD 4.
2 3 5 REVERSE ALIGNMENT METHOD WITH THERMAL 5. GROWTH ALLOWANCES
AND TEMPERATURE GROWTH FACTORS 2 3 5 5. VERTICAL PUMP ALIGNMENT 5 5
10 TOTAL HOURS FOR HEAT EXCHANGERS 24 26 50 9. MACHINE ALIGHMENT
ALIGNMENT BASICS PART 1 LESSON 1 ALIGNMENT BASICS PART 1 LECTURE
Objectives To understand the basic of alignment particularly the
importance of alignment and understanding of different factors
which woodheap to make alignment a best possible way. 1.0 ALIGNMENT
THEORY Misalignment is one of the most common faults found in
rotating equipment. Understanding how to properly diagnosis and
correct for misalignment in plant equipment and how to deal with
common pitfalls while out in the field is essential in doing the
job right the first time. The alignment of shaft centerlines on
coupled machines is one of the most important aspects of machine
installation. Contrary to popular opinion, flexible couplings will
not always compensate for even moderate amounts of shaft
misalignment. Misalignment is any condition in which the shaft
centerlines are not in a straight line during operation.
Misalignment generates unnecessary forces. Precision alignment
removes these forces resulting and cyclic forces resulting in
reduced vibration and noise levels, minimized shaft bending and
cyclic fatigue reduced energy costs, and increased bearing, seal,
and coupling life. Shaft centerline misalignment can be classified
as either angular or offset (also called parallel). Angular
misalignment occurs when the shaft centerlines meet at an angle.
Offset misalignment occurs when the shafts are parallel, but offset
from each other. The misalignment may be vertical, horizontal, or a
combination of the two. Most shaft misalignment is a combination of
both angular and offset misalignment. graphically illustrates the
alignment types. Another type of misalignment not associated with
couplings is bearing misalignment. the centerlines of two coupled
shafts can be properly aligned, but the bearings on one side of the
coupling may be misaligned. Bearings can be misaligned if they are
not mounted in the same plane; if they are cocked relative to the
shaft; or because of machine distortion due to soft foot, an uneven
base, or thermal growth. Lesson 1 Page 1 10. MACHINE ALIGHMENT
ALIGNMENT BASICS PART 1 2.0 ECONOMICS OF MISALIGNMENT There are a
number of cost benefits of precision alignment. It can help reduce
plant operating costs by reducing energy costs. Precision alignment
also results in increased maintenance savings through reduced parts
consumption and reduced overtime. Finally, it can help decrease
equipment downtime and increase product quality. A recent study
performed at the University of Tennessee found that even small
amounts of misalignment could significantly reduce bearing life.
The study found that if, on average, a motor was offset misaligned
by 10% of the coupling manufacturers allowable offset, there was a
corresponding 10% reduction in inboard bearing life. Furthermore,
if a motor was offset misaligned by 70% of the coupling
manufacturers allowable offset, there was a corresponding 50%
reduction in inboard bearing life (Hines et al). the results of the
table at the top of this page. 3.0 ALIGNMENT TOLERANCES Alignment
tolerances have often been treated with a halfhearted just get it
close attitude. But, alignment tolerances are actually the
measurement of a job well done and they provide the definition of
what close actually is. There are two reasons to use tolerances.
The key reason is to establish goals. If you know when the job is
finished. If there is not a goal, there cannot be a quality
alignment. Lesson 1 Page 2 11. MACHINE ALIGHMENT ALIGNMENT BASICS
PART 1 The second purpose of alignment tolerances is to establish
accountability. Accountability is the evaluation of alignment
quality. If there is no tolerance to compare an alignment to, how
can the quality to the alignment be judged? Accountability can
create competition, driving a mechanic to get the job done better.
Misalignment is one of the most common faults found in rotating
equipment. Because of the frequency of occurrence, machines are
often aligned with out taking the time to properly diagnose the
machine fault. Diagnosing misalignment in a machine can be
difficult because the vibration, phase, and temperature
characteristics are dependent. On the type of coupling used.
Misalignment leads to reduced bearing, seal and coupling life.
Precision alignment reduces plant operating costs through reduced
maintenance and energy costs as well as reduced equipment downtime.
Asset optimization is possible with a balance of Technology,
Expertise, and Work Processes. In theory, machine alignment is a
very straightforward process. With some type of measuring device
extended across the coupling, the shafts are rotated to several
positions (at least three) to determine the relative position
between them. Since alignment is a iterative process (meaning that
the misalignment should continuously decrease with each machine
move), it is theoretically only a matter of sufficiently repeating
alignment corrections until an acceptable solution is achieved. In
fact, quality alignment is not dependent on the type of measurement
system used. Any good dial indicator set or laser system should be
sufficient to perform quality alignments. Therefore, in heavy
industrial applications, where the cost of downtown can be in
excess of $ 10,000 per hour, the fundamental question for an
alignment program is not simply Can I successfully align the
machine? but rather fastest alignment solution so that I can start
production again? Furthermore, since misalignment is often
compounded by structural faults such as soft fool, piping strain,
induced frame distortion, excessive bearing clearance, shaft rub,
etc., it may not be possible to align the machine without first
addressing these additional problems. These pitfalls can turn an
otherwise simple alignment job into an all day affair frequently
with unsatisfactory result despite conscientious effort and a
considerable investment in manpower and downtime. Lesson 1 Page 3
12. MACHINE ALIGHMENT ALIGNMENT BASICS PART 1 For this reason, it
is crucial for the personnel performing alignments to be aware of
the kinds of structural faults that can complicate the alignment
process and that they learn to recognize the tell tale signs of bad
measurements before they invest valuable downtime in an
unproductive exercise. 4.0 COLLECTING VALID DATA Some fairly simple
yet powerful techniques can be applied to determine the validity of
alignment readings before investing time executing a machine move
that may be wrong. If using a dial indicator set, it is useful to
apply the data validity rule to each set of readings. The data
validity rule compares the readings taken at the four cardinal
positions: Top + Bottom = Left + Right. It provides a quick way to
determine the validity of an alignment solution before moving the
machine. This simple check is able to catch many set up errors and
mechanical faults such as: Loose brackets. Sticking indicators.
Indicators set too high or too low. Improperly recorded data values
and / or signs. Sleeve bearing float. Surface irregularities or
eccentricities. Excessive bearing clearance. Small deviations from
the validity rule are to be expected. If the difference is more
than 10%, it is possible that the coupling may be loose enough to
provide excess torsional play (backlash). To reduce the coupling
engaged while rotating the shafts from the driven machine in the
normal direction of rotation. If the error is greater that 20% the
cause should be determined. This could be a problem with the
alignment fixture(s) or a concern with the machine being aligned.
Alignment problems occur from loose fixtures or improper use of
fixtures. Possible machine concerns include locked couplings,
spalled bearings, machine binds, etc. If the data validity rule is
not checked when such a problem exists, these potential machine
faults will remain undetected and substantially complicate the
alignment process. Even worse, the objective of increasing machine
reliability through quality alignment will not be accomplished.
When using a laser alignment system, the potential for user error
is greatly reduced de to the automatic measurement and recording of
readings. However, the data validity rule can still be very useful
to indentify structural faults such as excessive Lesson 1 Page 4
13. MACHINE ALIGHMENT ALIGNMENT BASICS PART 1 bearing clearance and
other forms of structural looseness. To apply the validity rule
with a laser system, it is necessary to record all four cardinal
readings (top, bottom, left, right) and plug them into the formula.
If, however, the alignment solution is based on only three of the
four cardinal readings, the user will not have the ability to check
the validity of the solution. In one such example involving a feed
water pump in a power plant, an alignment was attempted using only
three of the four cardinal measurement (top, left, and right the
bottom reading was omitted). The machine was moved as indicated by
the laser system but on improvement in the alignment condition was
achieved. Numerous readings and machine moves were implemented but
failed to result in any improvement in the alignment condition.
When the reading for the fourth position (on the bottom) was
manually collected and the values were plugged into the equation,
it was clear that the validity rule was being violated. Visual
inspection of the machine train indicated that one of the feet on
the gearbox had been bolted down with the wrong size bolt head
thereby substantially reducing the hold down force at this foot.
This allowed the foot to lift slightly during shaft rotation
creating substantial error in the readings. After replacing it with
the proper size bolt, the operator was able to align the machine in
just a few moves. (Note: more advanced system are currently
available that will automatically apply the validity rule to the
obtained readings and indicate whether acceptable levels for
deviation have been exceeded.) It is important to realize that
otherwise straight forward alignment jobs can become highly complex
and yield unacceptable results if the technician does not address
the quality of the alignment measurement and potential frame stress
conditions (frame distortion, soft foot, and piping strain) during
the pre alignment check. These steps should all be conducted before
the technician ever begings to move the machine. 5.0 MOVING THE
MACHINE Every machine is considered moveable, even those with rigid
piping attached. Some machines are more easily moved than others.
The aligner has the option to move one or the other, or both
machines. Machines shall be adjusted with small, precise movements.
Excessive force, that could cause internal or external damage, is
to be avoided. Steel-hammer blows on bare steel or iron Lesson 1
Page 5 14. MACHINE ALIGHMENT ALIGNMENT BASICS PART 1 machine
housings are unacceptable. Hammering on wooden blocks is OK.
Jackscrews are the preferred movement method. Horizontal movements
shall be monitored with dial indicators, or other measuring
instruments, to know when to stop. "Bolt bound" conditions can be
handled in various ways, depending on the situation at the job
site. The following methods are allowable: 1. Moving both machines
2. Undercutting the bolt diameter to remove threads 3. Reducing
bolt size one nominal fractional size (i.e., 3/4 bolts to 5/8 bolts
is OK) 4. Enlarging the hole is OK if structural integrity is not
compromised 5. Tilting the machine with differential shimming After
all movement is done, the machines will be secured by tightening
the holddown bolts to the recommended torque in accordance with the
manufacturers instructions. If no instructions are available, the
torque values in Appendix D shall be used. After torquing the
holddown bolts, a final set of shaft-to-shaft readings will be
taken and reported as the final orientation. Doweling of machines
in place will not be done unless the installation instructions
specifically require it. 6.0 UNDERSTANDING DIAL INDICATOR A
positive reading indicates that the plunger is pushed inward and
the dial rotates in a clockwise manner, thus indicating a positive
reading. A negative reading indicates that the plunger is extended
outwardly and the dial rotates in a counter clockwise manner
indicating a negative reading. Dial indicators have many different
face designs and maximum indicator travel. It is important to
become familiar with the dial indicators and other measuring
devices that you are going to use. For the case where a dial
indicator is mounted on the driven equipment and the plunger
touches a surface on the driving Lesson 1 Page 6 15. MACHINE
ALIGHMENT ALIGNMENT BASICS PART 1 equipment. A positive value of
the difference between the top and bottom readings would indicate
that the plunger is depressed greater at the top, thus the axis of
the driving equipment (indicator plunger contacts this equipment)
is higher than the driven equipment. 6.1 OTHER HELPFUL HINTS WHEN
USING A DIAL INDICATOR Adjust indicator face to zero. Rotate shaft
one complete revolution and note the maximum positive or negative
value. Return the shaft to location of maximum value and readjust
face to zero. Rough align equipment to ensure that equipment to
ensure that equipment alignment is within the indicator total
travel. Make sure that supporting hardware is reliable and rigid.
Areas of attachment should be large enough for indicator supports
and clean for mounting 7.0 SHIMS MATERIAL The best choice for shim
material is stainless steel. This material is very stable and is
easy to maintain. Carbon steels should be avoided because it will
rust and eventually compromise the machinery alignment. Synthetic
or plastic shim material should be avoided for industrial
applications because it is easily damaged and under heavy load will
deform which compromises the alignment condition. The shims used
for industrial applications should be large enough to adequately
support each foot. Commercial shims are available in various
dimensions. These shims are precut and dimensioned to standard
thicknesses which are labeled on a small tab. These shims are easy
to install and are difficult to mix up. If shims are manufactured
in the field they should be large enough to support the machine
foot and all edges should be smoothed to eliminate burrs. Kinked or
otherwise damaged shims should be discarded and new ones obtained.
The shims, the base plate surface, and bottoms of the machine feet
should be clean and free of defects prior to installing any shims.
8.0 WHICH MACHINE MOVES? Generally, the stationary machine has
certain constraints which make it impractical to move it. Pumps
have rigid piping attached, generators have complex cooling
systems, and gear boxes are Lesson 1 Page 7 16. MACHINE ALIGHMENT
ALIGNMENT BASICS PART 1 relatively sensitive to any orientation
other that flat and level. When these machine types are moved the
attached systems must be relocated to eliminate sources of strain.
Multiple case machine trains, such as dual compressors driven by
one turbine, pose another problem. All three machine shafts must
operate co-linearly to function efficiently. By studying the
graphical plot of the current alignment and the desired alignment
it may prove most effective to move the center machine case,
instead of moving two or three machines. Energy is continuously
added to increase the fluid velocities within the machine to values
in excess of the occurring at the discharge such that subsequent
velocity reduction within or beyond the pump produces a pressure
increase. The categories of that pump are include all kinds of
centrifugal pumps and air lift pump and in lesson two they define
in detail. Lesson 1 Page 8 17. MACHINE ALIGNMENT ALIGNMENT BASICS
PART 2 LESSON 2 LECTURE ALIGNMENT BASICS PART2 Objectives This
lesson further explains the importance of alignment by mentioning
different damages which misalignment caures and important
preliminary to accomplish the 1.0 MISALIGNMENT EFFECTS 1.1 EFFECT
ON COUPLING The most affected part of a unit that suffers from
misalignment is the coupling. Regardless of the type employed on a
unit, either rigid or flexible, the coupling does not compensate
for gross permanent misalignment. Some people are of the opinion
that since the coupling is termed flexible it requires less
accurate alignment. This is not so. This type of coupling provides
allowances only for unintentional, unexpected, but ever present
short periods of misalignment created by the inherent
characteristics of the units operation. It is because these
flexible couplings are designed to accommodate these forces that
they do not fail as readily as bearings or seals, which are not
designed for any great amount of misalignment. 1.2 EFFECT ON
BEARING, SEALS AND SHAFTS Stresses that accompany misalignment also
have a severe effect upon bearings, both antifriction and plain,
thereby reducing their life. Proper alignment cannot extend the
natural life of an antifriction bearing. Misalignment can certainly
reduce their natural life. When the life of a bearing is
determined, it is done without misalignment forces being present.
1.3 SHAFT AND OTHER PARTS Most mechanical seals are designed to
function properly only when minimum shaft deflection is
encountered, thus, mechanical seals fail due to shaft deflection
created by misalignment. Unlike other mechanical problems which
begin as a minor deficiency and grow into something quite
noticeable and major, misalignment is Lesson 2 Page 1 18. MACHINE
ALIGNMENT ALIGNMENT BASICS PART 2 as severe the first revolution as
it is when the machine finally fails. This is the case when a
machine does not shift due to misalignment forces. It is through
this minor deficiency that the major failure can stem. It is true
that stresses from misalignment are in direct proportion to the
speed of the unit, with the amount of initial misalignment
remaining constant. Speed of unit should generally dictate the
tolerances allowed for alignment. Operating characteristics will
also govern initial and operating alignment tolerances. The
following discussion of shaft alignment is dependent on keeping
these thoughts of mind. 2.0 FACTOR AFFECTING ON ALIGNMENT Prior to
discussing the particular procedure to be employed on a given unit,
there are several factors that may mechanics either dont understand
or fail to consider.. 2.1 PIPING STRAIN Practically all
manufactures assembled units, both driver and driven on a common
base are factory alignment. This factory alignment only serves the
factory purpose to determine if and how the unit can be alignment
within its mechanical limits. Factory alignment was supposedly
obtained with the base in an absolutely level, unstressed position,
but when the unit grant and piping installed on it many undue
stresses are involved to disturbed the alignment. For achieving the
maximum possible factory aligned mechanical limit the unit must be
grout in a level foundation after that stage take a preliminary
alignment reading and record it. Install all piping on the pump and
electrical connection, checked and measure the alignment
distortion. This will allow noting any movement of the shafts
caused by stresses imposed by the piping . Stress relieving or some
other means of eliminating these stresses may have to be performed.
Additional pipe supports may be required. If blinds have been
placed in the lines during shut down, final alignment not be
performed until these have been removed. Note: On a installed unit,
when pump casing or piping removed for maintenance purpose and at
the time of reinstallation the piping strain can again activate.
Lesson 2 Page 2 19. MACHINE ALIGNMENT ALIGNMENT BASICS PART 2 2.2
DOWEL PINS AND PUMP CASING JOINTS On some unit dowel pins are
provided for exact pump casing joint, because it is very critical
to the proper operation of the pump. Manufacturers of these pumps
require that this joint be evenly loaded to insure proper operation
of that unit. Most pump designs allow a space at this joint. During
the assembly of the pump, the mechanic equalizes this space using
feeler gages. From this point on in the installation and alignment
of the pump, this space should not be disturbed. However, some
mechanics unwisely use this adjustable joint to achieve proper
alignment. By doing this, there is danger of reducing axial
impeller clearance at the tips of the impeller vanes. 2.3 PUMP
BEARINGS SUPPORT FIG. 1-1 If this type pump has an adjustable
support leg under the inboard bearing, it should not be secured
until the case joint clearance has been equalized. Then, with a
dial indicator monitor, pull this leg down 1 to 3 mils (.001 -
.003). This will insure proper support of that bearing without
placing an undue strain on the casing. Fig. 1-1. Pump Bearing
Support. Lesson 2 Page 3 20. MACHINE ALIGNMENT ALIGNMENT BASICS
PART 2 2.4 SOFT FOOTING All driver support feet must be on the same
plane. This condition is extremely important and should be one of
the first problem areas to be checked. Drivers with four or more
feet are the only ones to possible create this problem. The trade
name of that problem is known as Soft Footing . Fig. 1-2 The soft
footing created when one foot is slightly higher, or lower in
elevation. The soft footing created two major problems. Fig. 1-2.
Soft Footing. First exact alignment is very difficult to achieve,
because this foot is tightened down with the hold down bolt or nut
it must do one of two things it must spring the frame work and come
down or it must break the foot. The spring action create different
alignment reading and condition of this sort is a big handicap to
the person doing the alignment. Secondly, this condition of having
a soft foot will introduce undue stress within the unit itself.
Bearings, mechanical seals, seals, and wear rings suffer without
need. Vibration, parts breakage, and ultimate failure is possible
when this condition is not resolved. The shaft no longer runs
within a line bored bearing housing, one is displaced in reference
to the other. 2.4.1 METHOD FOR ELIMINATE SOFT FOOTING First point
for eliminate the soft footing, better used minimum number shims
rather than a bulk of small measurement shim because that can
create a spongy foot and that will behave as a soft foot. Secondly
if that is a permanent problem it must be eliminate by shimming
before the alignment. To eliminate the possibility of a soft foot,
attach a dial indicator to the support pedestal and set the
indicator button on top of one of the support feet. Zero the
indicator. Now loosen the support nut and read the indicator. If
the indicator is deflected more than 3 mils move to the adjacent
foot and take a Lesson 2 Page 4 21. MACHINE ALIGNMENT ALIGNMENT
BASICS PART 2 reading in the same manner. If the reading on the
second foot exceeds the first reading, the second foot should be
shimmed. Repeat this procedure until you obtain an indicator
reading of less than 3 (0.003) mils when one foot is loosened and
the others are tight. 2.5 MAGNETIC CENTER An electric motor is said
to run in its magnetic center. This means that the rotor is pulled
into operating position by the magnetic force whenever the motor is
running. For this reason the coupling length can not be determined
when the machine is at rest unless a mark has been made, showing
the running position. If there is no mark the motor must be started
to see just where the shaft moves to, while it is running. Then the
coupling spool is made up to suit the distance between couplings
for operating conditions. Also lock the axial movement of the shaft
while aligning, because that axial movement differ the each face
reading. 2.6 SHAFT DEFLECTION, COUPLIGN WEAR AND UNEVEN BEARING
WEAR The shaft deflection affects the concentricity of the center
line and causes of misalignment. The coupling wear in case of that
when rotating only one coupling for alignment can affects the
parallelism of the two mating halves of coupling and causes
misalignment. Uneven bearing wear again affects the concentricity
of the shaft center line, the same as in the case of shaft
deflection. The above mention factors must be checked before a
alignment job started by runout reading. For taking run-out reading
the dial magnetic base fixed on the base plate and dial on the
coupling OD and set it zero. The shaft is rotated and the indicator
observed to see if the permitted amount of deflection is not
exceeded. 2.7 HEAT GROWTH (PURPOSE OF HOT CHECK) Lesson 2 Page 5
22. MACHINE ALIGNMENT ALIGNMENT BASICS PART 2 Since there is a
temperature change in a unit from the shut down temperature to the
running temperature, we can also expect to have a dimensional
change caused by this change in temperature. Depending upon the
design and service of the unit, this change in dimension will vary
in amount and direction. This is why a hot check is vital to proper
alignment. As a rule, hot alignment is performed when there is a
temperature difference between driver and driven of 150 degrees or
more. Here again this is a general rule. Each particular unit will
determine how it is to be aligned. Basically there are two concepts
about a hot check. One concept is to achieve perfect alignment,
unit aligned in cold and then put the unit on stream. Once the
operating temperature are reached, the unit is shut down and
alignment is again checked. Additional moves are made once the unit
is cold again to compensate for hot movement. There are several
disadvantages to this method. First is the fact that an additional
shim change time will be required. Time consumed for dimensional
changes and shut down The second concept of hot alignment is that
of knowing where the unit will go. If the facts are not known as to
the units movement, it is easy to second guess the units movement,
if the facts, or calculations, are correct as to where the unit
will move, the unit will align itself. If it does not, at least it
will move in the desired direction. One apparent advantage of this
concept is that it is possible not be forced into an additional
shim changed based upon hot readings. There is one limitation. If
cold alignment is drastically off, as in the case with a steam
turbine driving a cold service pump, putting the unit on stream
should be done slowly and cautiously to allow warm up and
positioning of the shafts. Nearly all units are aligned cold with
allowances made for expected thermal growth. Regardless of whether
these allowances have been made or not, a hot check should be
performed. This check will confirm the hot position of the shaft
3.0 ALIGNMENT TOLERANCES Perfect alignment is the desired objection
but in the practical field and in many cases the achievement of
(0.00) alignment reading is quite difficult and time consuming job.
So the alignments for a unit can accept with some tolerances.
Remember a stock set of alignment tolerances which are suitable for
all of industry just simply does not exist. As key a good alignment
tolerances for a given unit is one which permit the unit to run
without creating forces great enough to causes Lesson 2 Page 6 23.
MACHINE ALIGNMENT ALIGNMENT BASICS PART 2 the components to fail
prematurely. According to that view forces generated by
misalignment are directly related to the speed of the shafts, it is
logical to use speed as the governing agent to establish alignment
tolerances. Economics is the other factor for establishing the
acceptable tolerances. For example, a pump which requires a new
seal every six weeks would hardly warrant the time required to
establish perfect alignment. This is especially true when the
shafts can be placed within tolerance within a an hour or so. On
the other end of the spectrum is a unit which is not planned to
come down in two years. The extra time required to achieve perfect
alignment is justified. Some people in industry use the vibration
caused by misalignment as the criteria for alignment tolerances,
but a practical expenses, that a very low tolerances can be double
without an appreciable change in the amplitude of vibration. Listed
below are some tolerances that are based upon speed and generally
accepted in production industries. The slow speed range will
encompass the majority of electric and steam driven units. SLOW
SPEED 3550 RPM & Below 5 Mils on OD 3 Mils on Face HIGH SPEED
3600 RPM & Above 2 Mils (TIR) on OD 1 Mil (TIR) on Face
Flexible coupling manufacturers describe the capabilities of their
couplings on the basis of maximum angular misalignment, among other
things. This is the amount at which their coupling will still
function. Lesson 2 Page 7 24. MACHINE ALIGNMENT ALIGNMENT BASICS
PART 2 This can hardly be used as the criteria for establishing
alignment tolerances. 4.0 MISALIGNMENT DETECTION It should be noted
that misalignment can be detected while the machine is in
operation. Forces caused by misalignment will create vibration as
mentioned before. The characteristics of this vibration is what can
be used to determine a condition of misalignment. It specially is
the direction of this force that is the key, a high axial force. A
high axial force is generated when the misalignment is primarily
angular. This is influenced to a large extent by the type of
coupling transmitting the forces. When the type of mis-alignment is
primarily OD, or parallel, the axial forces subside and a larger
radial force is evident as shown in Fig. 1-3. To determine where
the forces are and in what direction they are in is a simple task
provided an adequate instrument is available. Fig. 1-3. A is
measuring Axially and B is measuring radially vibration for
detecting misalignment. The most effective manner to confirm
misalignment is with dial indicators. As was mentioned earlier, the
alignment of two shafts can Lesson 2 Page 8 25. MACHINE ALIGNMENT
ALIGNMENT BASICS PART 2 be well outside the tolerances normally
established and still not produce an alarming vibration level. This
is due primarily to the type coupling employed and the type of
misalignment in the unit. Each type of misalignment has its own
characteristics of vibration and dial indicator readings. 5.0 TYPES
OF MISALIGNMENT Basically, there are three conditions that may
exist for misalignment. As shown in Fig. 1-4, the shaft are
parallel to each other but offset somewhat. This condition is known
by several terms. 5.1 PARALLEL MISALIGNMENT But more commonly by
parallel or, better yet OD. Shaft center lines do not intersect to
correct for this condition movement is made for one half the TIR of
OD indicator. Fig. 1-4. OD Displacement. 5.2 ANGULAR OR FACE
MISALIGNMENT This type of misalignment is represent by Fig. 1-5
should be noted that the shaft center lines intersect at only one
point, as opposed to being concentric. Any adjustments to this
condition should be made against TIR of face Indicator. Fig. 1-5.
Angular or Face Displacement. Lesson 2 Page 9 26. MACHINE ALIGNMENT
ALIGNMENT BASICS PART 2 5.3 MISALIGNMENT BY COMBINATION OF ANGULAR
& PARALLEL That condition involves a combination of these two
condition as shown in Fig. 1-6. Fig. 1-6. Angular Parallel
Displacement. In order to make the task of shaft alignment more
interesting, we must cope with these conditions in both the
horizontal plane, looking at the side of the unit, and in the
vertical plane, looking down on the unit. Again, the utopia is to
get these shafts on a concentric center line throughout their
entire length, or TIR OD of O and TIR FACE of O in both planes
during the hot check. Depending upon speed and unit, deviation from
the exact alignment can be tolerated. The specific procedure that
should be, or better yet can be, used to align the shafts will be
governed primarily by the unit. Since there is an unlimited number
of different sizes and types of units requiring alignment, lets
narrow this down to three categories. Each category is a separate
procedure; two indicator, Reverse Indicator, and Dynamic to Static
Methods. 6.0 ALIGNMENT RECORDS Regardless of the procedure employed
for shaft alignment, a sound set of records should be maintained
for each particular unit being aligned. These records not only aid
the mechanic during the aligning process, but also serve as
permanent record for future alignment. The record shown in Fig. 1-7
was designed for one particular procedure of alignment, the
Indicator Reverse Method. With very minor alternations, this same
form can be used for each particular procedure discussed in this
study. The majority of the form is self- explanatory. However, on
each procedure the reference of direction is Lesson 2 Page 10 27.
MACHINE ALIGNMENT ALIGNMENT BASICS PART 2 essential. This form
provides for the location of North. Any direction is suitable but
North is generally used. Direction will prove to be of great value
when determining lateral shifts. Inside the circles are located a
portion of an arrow. It should be completed to show the direction
of rotation of the unit, which is also the direction the shafts
were turned to obtain Indicator readings. Fig. 1-7. Alignment
Record Sheet. Lesson 2 Page 11 28. MACHINE ALIGNMENT ALIGNMENT BY
RIM & FACE METHOD LESSON 3 LECTURE ALIGNMENT BY RIM AND FACE
METHOD DETAILED PROCEDURE BY CALCULATION AND GRAPH Objectives This
lesson provides information in simple way to accomplish the
alignment by rim and face method by formula and graph. You can use
the Rim & Face Method to perform a calculated precision
alignment process. You may use a variety of shaft alignment
fixtures. We recommend that you use a commercial package designed
to accommodate a variety of shaft diameters. The fixtures should
include an assortment of rods to span various coupling lengths.
These packages expedite the precision alignment process. Also, sag
values can be pre-determined for the standard rod assortment. To
perform the Rim & Face Method, you must: Mount the dial
indicators fixtures. Measure the A, B, & C dimensions. Obtain
as-found readings. Determine the vertical foot positions. Make
vertical corrections. Make horizontal corrections. Re-measure and
record final alignment values. 1.0 UNTING THE DIAL INDICATOR
FIXTURES 1. To mount the fixtures follow these steps: 2. With the
coupling broken, mount the fixture to the stationary shaft or
coupling hub. 3. Span the coupling with a rod. 4. Rotate the
fixture to 12:00. 5. Attach the face dial indicator. The dial
indicator plunger must be centered for equal positive and negative
travel. 6. Attach the rim dial indicator. The dial indicator
plunger must be centered for equal positive and negative travel.
2.0 FIXTURE MOUNTING PRECAUTIONS Lesson 3 Page 1 29. MACHINE
ALIGNMENT ALIGNMENT BY RIM & FACE METHOD Regardless of the
specific hardware being used, the following precautions should be
observed. Never attach the fixture to the flexible portion of the
coupling. Maximize the sweep distance of the face dial indicator
for the geometry of the machine being aligned. If the face dial
contacts the coupling facedirectly, ensure the plunger of indicator
contacts the coupling near its outer edge. Ensure fixtures are
mounted at a position where rotation is possible. It is desirable
to have 360 degrees of rotation. Before obtaining alignment
measurements, determine dial indicator bar sag of the rim dial
indicator and ensure dial indicator readings are valid and
repeatable. Fig1 1 The A Dimension is the diameter of face
indicator travel. The A Dimension should be slightly less than the
coupling diameter. This is the most critical dimension. Measure A
very carefully. Lesson 3 Page 2 30. MACHINE ALIGNMENT ALIGNMENT BY
RIM & FACE METHOD 2. The B Dimension is the distance from the
rim indicator to the front foot bolt center. This dimension is
measured parallel to the shaft. 3. The C Dimension is the distance
between front and rear foot bolt centers. This dimension is
measured parallel to the shaft. 3.0 OBTAINING AS-FOUND READINGS To
obtain a complete set of as-found readings, perform the steps
below: 1. Rotate the dial indicators to 12:00. 2. Set the rim dial
indicator to the positive sag value. 3. Set the face dial indicator
to zero. 4. Record the setting of both dials at 12:00. 5. Rotate
the dial indicators to 3:00. 6. Determine and record the reading on
both dials. 7. Rotate the dial indicators to 6:00. 8. Determine and
record the reading on both dials. 9. Rotate the dial indicators to
9:00. 10. Determine and record the reading on both dials. 11.
Rotate the dials to 12:00 and ensure both dials return to their
original setting. Document as-found results using a format similar
to that shown below. Fig 2 4.0 MEASURING & INTERPRETING
VERTICAL MISALIGNMENT To measure vertical misalignment, perform the
following steps: Lesson 3 Page 3 31. MACHINE ALIGNMENT ALIGNMENT BY
RIM & FACE METHOD 1. Rotate the dial indicators to 6:00. Fig 3
2. Set the face dial indicator to read zero. 3. Set the rim dial
indicator to the sag value. 4. Rotate both shafts (if possible) to
12:00. Fig 4 5. Record the DIR and DIF dial indicator TIR values.
To determine offset and angularity from the 12:00 TIRs, use the
following rules: Coupling Offset = Rim Dial (DIR) TIR 2 Shaft
Angularity = Face Dial (DIF) TIR A dimension Lesson 3 Page 4 32.
MACHINE ALIGNMENT ALIGNMENT BY RIM & FACE METHOD 5.0 MEASURING
& INTERPRETING HORIZONTAL MISALIGNMENT To measure horizontal
misalignment, perform the following steps: 1. Rotate the dial
indicators to 9:00. Fig 5 2. Set both dial indicators to zero. 3.
Rotate both shafts to 3:00. Fig. 6 4. Record the DIF and DIR dial
indicator TIR values. To determine offset and angularity from the
3:00 TIRs, use the following rules: Coupling Offset = Rim Dial
(DIR) TIR 2 Shaft Angularity = Face Dial (DIF) TIR A dimension
Lesson 3 Page 5 33. MACHINE ALIGNMENT ALIGNMENT BY RIM & FACE
METHOD 6.0 CALCULATING THE FRONT AND REAR FEET POSITIONS Front foot
position calculation: = ( Face TIR x B) + 1/2 Rim TIR A Rear Foot
position calculation: = ( Face TIR x (B+C)) + 1/2 Rim TIR A
Positive values mean the foot is high, shims must be removed.
Negative values mean the foot is low, shims must be added. 7.0
RIM-FACE CALCULATION PRECAUTIONS 1. Ensure the rim and face dial
indicator TIRs are properly determined from the dials prior to
performing calculations. 2. Be careful NOT to make mathematical
errors when subtracting signed numbers. 3. Observe parentheses in
the equations. Perform operations inside parenthesis first. 4. Do
NOT make human errors substituting real values into the equations.
Lesson 3 Page 6 34. MACHINE ALIGNMENT ALIGNMENT BY RIM & FACE
METHOD 5. Ensure the A, B, and C dimensions are accurate and are
properly entered into the equations. 4 8.0 CONSTRUCTING A RIM-FACE
GRAPH To construct a scaled Rim-Face graph, perform the following
steps: 1. Obtain graph paper with 10 divisions between bold lines.
2. Turn the graph paper so that the long side is horizontal. 3.
Draw a horizontal line at the center of the page. This line
represents the stationary shaft center and is drawn across the page
midway down the graph dividing the page. It is helpful if this line
is on top of one of the bold lines. 4. Determine the horizontal
plotting scale. Always use the largest scale possible. Measure the
distance from the stationary indicator plunger to the center-line
of the rear feet of the movable machine. Standard graph paper is
about 10 inches across. The largest horizontal scale will be the
machine distance divided by the page width. Note your horizontal
scale. 5. Make a vertical line on the extreme left of the
horizontal line. This mark represents the point where the rim dial
indicator contacts the shaft or coupling hub and is labeled: DIR.
6. Make a second vertical line representing the point along the
shaft length of the front feet of the movable machine (RF). 7. Make
the third vertical line representing the point along the shaft
length of the rear feet of the movable machine(RF) Lesson 3 Page 7
35. MACHINE ALIGNMENT ALIGNMENT BY RIM & FACE METHOD Fig.7 9.0
PLOTTING OFFSETS After setting up the graph, the next step is to
plot two offset points. One is the offset measured in the plane of
the rim dial indicator (DIR). The other offset point is derived
from the face dial indicator (DIF) reading and the A dimension. To
plot the offsets, perform the following steps: 1. Determine the
vertical scale. The vertical scale is typically 1 mil (0.001) per
division. In cases of gross misalignment where the offsets will not
fit on the page, a larger scale, such as 2-3 mils per division, is
sometimes required. 2. Plot the offset from the rim dial indicator
on line DIR. Use the horizontal line representing the stationary
shaft centerline as the reference. All points above this horizontal
line are positive (+) and all points below the line are negative
(-). Ensure you divide the Rim Dial TIR by 2 to obtain an offset
value. 3. Plot the second offset point using the shaft slope (Face
TIR / A dimension). Lesson 3 Page 8 36. MACHINE ALIGNMENT ALIGNMENT
BY RIM & FACE METHOD Plot this point counting from the DIR
offset point! In the rim-face graph example below, the DIR offset
is - 10 mils and the shaft slope is + 4 mils over an A dimension of
5. Fig.8 10.0 DETERMINING MOVABLE SHAFT POSITION After plotting the
two points, to determine the movable shaft position perform the
following steps: 1. Using a ruler or straightedge, draw a line
through the two offset points that extends to the rear feet of the
movable machine. 2. Count the number of squares in the plane of the
front and rear feet to determine the position and corrections
needed. In the example below, the feet of the machine are 2 mils
low; shims need to be added. The rear feet are positioned 6 mils
too high; shims need to be removed from both rear feet. Lesson 3
Page 9 37. MACHINE ALIGNMENT ALIGNMENT BY RIM & FACE METHOD
Fig.9 11.0 RIM-FACE GRAPHING PRECAUTIONS 1. Ensure proper
horizontal and vertical scaling techniques are consistently used.
2. Always double check the position of vertical lines drawn to
represent the DIR, FF, and RF. 3. Ensure the two plot points are
properly determined from TIRs. 4. Ensure positive offsets are
plotted above the horizontal reference line and negative offsets
are plotted below the line. 5. When interpreting the graph to
determine the movable shafts front and rear feet positions in the
vertical plane, observe the following rules: If the movable shaft
is above the horizontal stationary shaft reference line the shaft
is too high. Lesson 3 Page 10 38. MACHINE ALIGNMENT ALIGNMENT BY
RIM & FACE METHOD If the movable shaft is below the horizontal
stationary shaft reference line, the shaft is too low. 6. When
interpreting the graph to determine the movable shafts front and
rear feet positions in the horizontal plane, view the graph the way
you view the machine, that is, standing behind the movable machine
facing the stationary machine. Also observe the following rules: If
the movable shaft is above the horizontal stationary shaft
reference line the shaft is positioned to the right. If the movable
shaft is below the horizontal stationary shaft reference line, the
shaft is positioned to the left. 12.0 MAKING VERTICAL CORRECTIONS
To correct vertical misalignment, follow the steps below: 1.
Determine the vertical position of the movable machine using
calculation and/or graphing techniques. Positive values at the feet
mean that the movable machine is high, therefore you will remove
shims. Negative values mean that the movable machine is low, so you
will add shims. 2. Make shim changes to both front feet and both
rear feet as needed. 3. Always check shim thickness with an outside
micrometer. Precut shims aren't always what they're marked; many
shim manufacturers designate shims with the nominal thickness. 4.
Use consistent and correct torquing procedures. 5. As shim changes
are made, check for and take precautions to avoid creating soft
foot conditions. Lesson 3 Page 11 39. MACHINE ALIGNMENT ALIGNMENT
BY RIM & FACE METHOD 13.0 MAKING HORIZONTAL CORRECTIONS To
correct horizontal misalignment, follow the steps below: 1. Rotate
the dial indicators to 9:00 and zero them. 2. Rotate both shafts
(if possible) to 3:00. 3. Adjust the dial indicators to one-half
values. 4. Move the front feet of the movable machine as you watch
the rim indicator move to zero. 5. Move the rear feet of the
movable machine as you watch the face indicator move to zero. 6.
Repeat steps 4 & 5 until both dial indicators read zero. Fig.10
Lesson 3 Page 12 40. MACHINE ALIGNMENT REVERSE INDICATOR METHOD
LESSON 4 LECTURE REVERSE INDICATOR METHOD BY FORMULA AND
GRAPHDETAILED PROCEDURE Objectives This lesson provides information
in simple way to accomplish the alignment by reverse indicator
method both by formula and graph. 1.0 INTRODUCTION The dial
indicator reverse method of shaft alignment is the most accurate
procedure. By using conventional tools and instrument, achieve a
great amount of accuracy in minimum time. In this method two dial
indicator are fixed on the both couplings rims, just exactly
reverse to each other, and all reading taken on the two coupling
rims. As mention in Fig. 4-1. Since the face reading does not
involve in this procedure, the thrust and axial float does not
affect the reading obtained and that is the major advantage of this
procedure. 2.0 WHERE THIS PROCEDURE APPLIED Since this procedure of
alignment have many advantages and use of this procedure a is
limited only by the characteristics of the unit itself. Here are
some advantages and use limits. Considered these as a general. Fig.
4-1. Reverse Indicator Method. Lesson 4 Page 1 41. MACHINE
ALIGNMENT REVERSE INDICATOR METHOD 1. This method is preferred when
the distance between the adjacent shaft ends greater than one half
the coupling diameter. 2. It is preferred especially for large
equipment operating at high speed. 3. This method is also preferred
when coupling run-out cannot be eliminate. 4. When one or both
shafts have end float or have axial movement of the shaft. 5. also
preferred, when gear type couplings are used. 6. More over this
procedure can be used for all kind of equipment due to its accuracy
in a very short time. 3.0 DETAILED STEPS OF PROCEDURE Any procedure
that is effective has a definite outline. It was proven in the Two
Indicator Method and will be proven in this procedure. Since both
are procedures to achieve alignment of two rotating shafts, each
has steps that are common to each other. The discussion of the
steps in the previous procedure are applicable to this procedure.
3.1 LOCK OUT 3.2 CLEAN FEET & PADS 3.3 DETERMINE INDICATOR SAG
& RECORD If using two brackets, check the sag for both brackets
list the sag for the driver to driver bracket. 3.4 PROVIDE FOR
COUPLING GAP 3.5 ROUGH ALIGN 3.6 ELIMINATE SOFT FOOT 3.7 COMPLETE
RECORD SHEET WITH INFORMATION & DIMENSION a) Measured the
distance from the bracket to the post and record as mention in Fig.
4 - 2. b) Measure the distance from the center of the bracket to
center of the in board feet and record it. c) Measure the distance
from the center of the bracket to center of the out board feet and
record it Lesson 4 Page 2 42. MACHINE ALIGNMENT REVERSE INDICATOR
METHOD 3.8 TAKE A ROUGH ALIGNMENT BY STRAIGHT EDGE AND MINIMIZE THE
SIDE TO SIDE DIFFERENCE UP TO THE POSSIBLE LIMITS 3.9 TAKE READINGS
a. First of all dial indicators are attached to each half coupling
hub using brackets - see Figure 4 -2. The indicator on the
stationary machine hub (usually the driven machine) is set to zero
at point 1. The indicator on the moveable machine hub (usually the
driver) is set to zero at point 2. Points 1 and 2 must be 180
apart. b. Both shafts are turned together clockwise 90 and
indicator readings are recorded. This process is repeated until
four sets of readings on each hub are recorded. The readings are
checked for consistency, and another entire set of readings is
taken. If readings are not repeatable, the problem must be found
and eliminated in the machinery, the tools, or the method.
Equipment I.D. : __________________ Date______________________ Type
of Unit : __________________ Date of Last Alignment______ Running
Sped : ___________________ KW:______________________ Coupling :
Manufacturer ___________ Type: _____________________ Coupling
Manufacturers tolerances : Angular ________Parallel _________
Notes:___________________________________________________ ____
________________________________________________________ ____
Coupling Bracket I.D.: ______________ Bracket Deflection:
__________ Movable Machine: _________________ Stationary Machine:
_________ Lesson 4 Page 3 43. MACHINE ALIGNMENT REVERSE INDICATOR
METHOD Fig. 4-2. Alignment Record Sheet. Lesson 4 Page 4 44.
MACHINE ALIGNMENT REVERSE INDICATOR METHOD Fig. 4 -2. Position of
Brackets Viewer. 3.10 CORRECT FOR SAG From previous discussions we
know that indicator bracket sag only directly affects the bottom OD
reading. We also know that it is a negative value. To correct for
sag we simply subtract it, algebraically, from the bottom OD
reading. Each bracket has a different value for sag and each must
be handled independently. Lesson 4 Page 5 45. MACHINE ALIGNMENT
REVERSE INDICATOR METHOD 4.0 USING ANALYTICAL METHOD FOR
CALCULATING SHIMS (FOLLOW THE FIG. 4 -4) Fig. 4 -4. Sample diagram
of reading and shaft positions. Lesson 4 Page 6 46. { } x D { } x D
{ } x D { } x D MACHINE ALIGNMENT REVERSE INDICATOR METHOD 4.1
VERTICAL MOVEMENT BA is the bottom reading at coupling A BB is the
bottom reading at coupling B D1 is the distance between couplings
D2 is the distance between coupling A and front support feet of
movable machine.. D3 is the distance between coupling A and back
support feet of moveable machine Now:- i. The shim correction
required at front support feet. BA + BB 2 2 D1 - BA 2 ii. The shim
correction require at back support feet. BA + BB 3 2 D1 - BA 2 4.2
HORIZONTAL MOVEMENT Normally for the horizontal alignment, no need
of calculation but if machine is large and have jack bolts then
this calculation is helpful for accurate horizontal movement. For
horizontal movement dial set ZERO at left side and take the reading
on the right side of the coupling. * RA is the right side reading
on coupling A * RB is the right side reading on coupling B iii.
Movement required at front support feet. RA + RB 2 2 D1 - RA 2 iv.
Movement required at back support feet RA + RB 3 2 D1 - RA 2 Lesson
4 Page 7 47. } x 12 MACHINE ALIGNMENT REVERSE INDICATOR METHOD
Example: Fig. 4 -5. Fig. 4 -5. VERTICAL MOVEMENT Shim correction
required at front support feet. { BA + BB 2 } x D2 D1 - BA 2 BA =
-10 BB = + 20 D1 = 8 D2 = 12) D3 = 24 { 10 + 20 2 8 - (-10) 2 10 2
x 12 8 + 5 = 12.5 Add 12.5 Thou shims at front support feet. Shim
correction required at back support feet. { BA + BB 2 } x D3 D1 -
BA 2 Lesson 4 Page 8 48. } x 24 { } x D } x 12 { } x D } x 24
MACHINE ALIGNMENT REVERSE INDICATOR METHOD { 10 + 20 2 8 - (-10) 2
10 2 x 24 8 + 5 = 20 Add 20 thou. Shims at back support feet.
Movement required at front support feet = RA = R - L = -15 - (+5) =
- 20 RB = R - L = 6 - 14 = -8 RA + RB 2 2 D1 - RA 2 { (20) + (-8) 2
28 2 x 8 - 12 8 + 10 (-20) 2 = -21 + 10 = -11 Move 11 thou. Towards
right. Movement required at back support feet = RA + RB 3 2 D1 - RA
2 { (20) + (-8) 2 28 2 x 8 - 24 8 + 10 (-20) 2 = -32 Move 32 thou.
Towards right. Lesson 4 Page 9 49. MACHINE ALIGNMENT REVERSE
INDICATOR METHOD 5.0 ALIGNMENT PROCEDURE Outline of Alignment
Procedure Step 1: Familiarize with terms, techniques and procedure.
*follow all safety rules and procedures* Step 2: Learn about the
machine you are aligning. a. Visually check coupling, pipehangers,
base bolts, coupling spacing etc. b. Check for coupling & shaft
run out. Step 3: Know the characteristics of your tool. Perform a
Sag Check Step 4: Prepare the machine. a. Remove all existing shims
from under the feet-if old shims are to be used, clean them
thoroughly. -always use minimum amount of shims. b. Clean the base
thoroughly. -scrape and file away all rust, nicks, and burrs c.
Examine the base bolts and holes.-retap if necessary - replace
bolts if necessary Step 5: Installation of alignment brackets a.
Clean mounting surface, file off nicks and burrs. b. Check
indicators for sticking and loose needle. c. Aim indicator stem
directly toward center line of shaft. Step 6: Measurement - measure
distance between the two indicators - measure distance between
indicator and front feet. - measure distance between front and back
feet. Step 7: Layout graph paper - mark indicator position - mark
feet position. - remember to mark + and - signs (this eliminates
confusion) example: graph layout Lesson 4 Page 10 50. MACHINE
ALIGNMENT REVERSE INDICATOR METHOD Step 8: Preliminary Horizontal
Move Step 9: Check for Soft Foot Step 10: Perform Vertical Move
Step 11: Tighten all bolts and recheck indicator readings. Step 12:
Remove alignment brackets. 6.0 LEARNING HOW TO GRAPH PLOT Graphical
alignment is a technique that shows the relative position of the
two shaft centerlines on a piece of square grid graph paper. First
we must view the equipment to be aligned in the same manner that
appears on the graph plot. In this example we view the equipment
with the "FIXED" on the left and the "MOVEABLE" on the right. This
will remain the same view both vertically and horizontally. Lesson
4 Page 11 51. MACHINE ALIGNMENT REVERSE INDICATOR METHOD Scale:
Each Square = 1.0" Scale: Each Square = .001" Measure: A. Distance
between indicators = 10" B. Distance between indicator and front
foot = 5" C. Distance between feet =11" To eliminate confusion the
plus and minus signs should be marked on the graph. Graph paper
layout 7.0 VERTICAL MOVE Lesson 4 Page 12 52. MACHINE ALIGNMENT
REVERSE INDICATOR METHOD The vertical move is the part of the
alignment process that aligns the two shaft's centerlines nto their
proper up and down position. Usually you will have to add or remove
shims in this step. The indicators are zeroed on the top and read
at the bottom. (start with a plus + reading if you need to
compensate for sag) Example: the indicator on the motor pump -12
the indicator on the motor reads +8 This means that the shafts are
one half the total indicator reading from being collinear at these
points. Using a square grid graph paper to illustrate the position.
Under the indicator position mark the point that is half the
indicator reading. ( -6 for pump side indicator and +4 for the
motor side indicator) Connect these two points with a line and then
continue the line past the lines representing the feet on the
motor. The graph now shows that the front foot needs to have a
.003" shim added and the back foot needs to have a .001" shim
added. Now with your shims in place. Tighten all bolts and take and
check your readings. If the readings are within tolerance than your
equipment should be aligned. Lesson 4 Page 13 53. MACHINE ALIGNMENT
REVERSE INDICATOR METHOD 8.0 HORIZONTAL MOVE The horizontal move is
the part of the alignment process that aligns the shaft's
centerlines from side to side. View the machine from the pump end,
zero the indicators on the left, and then rotate and read on the
right. Make sure that you always view the pump from the same
direction in order for you to keep the left and right directions
correct. There is no sag compensation on the horizontal move. For
example: the indicator on the pump reads 8 the indicator on the
motor reads +10 The shafts are collinear at 1/2 the Total Indicator
Reading. Using graph paper to illustrate the position. Under the
indicator position mark the point that is 1/2 the indicator
reading. (-4 for the pump and +5 for the motor) Connect these
points and extend the line past the motors feet. This will show you
how much you need to move the motor for horizontal alignment. These
indicator readings mean that you need to move the motor: front foot
.006" left back foot .007" left Lesson 4 Page 14 54. MACHINE
ALIGNMENT REVERSE INDICATOR METHOD You can avoid graphing the
horizontal move by zeroing the indicators on the left and rotate
them to right. Now turn the indicator needles half way to zero and
begin to walk the motor into place by moving the fartherest foot
toward zero and then the nearest foot. Slowly walk the motor into
place by alternating the moves until you obtain two zero indicator
readings. Now begin the procedure for the vertical move. Be sure to
check your equipment for sag and soft foot. Lesson 4 Page 15 55.
Machine alignment Reverse Alignment Method With Thermal Growth
LESSON 5 LECTURE REVERSE ALIGNMENT METHOD WITH THERMAL GROWTH
ALLOWANCES AND TEMPERATURE GROWTH FACTORS Objectives To perform
alignment by reverse indicator method taking into account different
thermal position or growth factor calculation. 1.0 REVERSE
ALIGNMENT METHOD Before the machines can be successfully aligned,
the desired Ambient Condition positions must be determined. Once
both the present and Desired readings are ascertained, the
necessary vertical and horizontal moves can be computed. Although
the corrective adjustment may be plotted on suitable graph paper,
mathematical computations offer greater accuracy. However, for
demonstration purposes, both methods will be used in the following
example. 2.0 CALCULATING THE ADJUSTMENTS 2.1 DESIRED STATE OFFSET
INDICATOR READINGS AT AMBIENT CONDITIONS Readings recommended by
the manufacturer necessary to compensate for thermal movement, in
hopes of achieving collinear alignment at normal service condition.
Fig. 1-1 2.2 PRESENT STATE INDICATOR READINGS OBTAINED AT AMBIENT
CONDITIONS Lesson 5 Page 1 56. Machine alignment Reverse Alignment
Method With Thermal Growth Fig.1-2 2.3 ALIGNMENT LANGUAGE 1.
Ambient Condition: A machine is considered to be at AMBIENT
CONDITION when it is shutdown, blocked in, and hascooled until its
temperature has equalized to atmospheric conditions with lube oil
on. 2. Service Conditions: A machine is considered to be at SERVICE
CONDITION when it is stabilized at its normal operating condition.
3. Collinear Alignment: A machine is con. sidered to be COLLINEAR
ALIGNED when the shafts are in the same straight line (no
misalignment). 4. Offset: Offset is the measured distance from the
shaft center of one machine, to the projected center line of the
second machine. Vertical offset is measured from top to bottom.
Horizontal offset is measured from left to right. 5. Total
Indicator Reading (TIR): The differential between two indicator
readings obtained 1800 apart. When zeroed at the top and rotated
1800 to the bottom, the reading obtained is the vertical total
indicator reading. If the indicator was zeroed at the left side and
rotated 1800 to the right side, the reading obtained would be
horizontal total indicator reading. The total indicator reading is
always twice the offset. 6. Offset (TIR): Same as 4 above but
expressed in total indicator readings. 7. Sweep Readings: The Sweep
Readings are the readings obtained by sweeping the coupling 3600
with the dial indicator and noting readings at 900 intervals. The
readings are taken at Top (T), Right (R), Bottom (B), and Left (L)
of coupling being indicated. Lesson 5 Page 2 57. Machine alignment
Reverse Alignment Method With Thermal Growth 8. Present State: A
machine's present state is the bench mark of an alignment problem.
This is the original misalignment at ambientcondition prior to
making any corrections. 9. Desired State: A machine's desired state
is the alignment target. This is the desired ambient condition
alignment offset needed to compensate for the thermally - induced
movement to be incurred between ambient and service conditions. 10.
Final Readings: Readings obtained after the final adjustment has
been made. 11. Indicator bracket sag is the amount of deflection by
the indicator bracket attachment induced by gravity force. A
correction for this deflection should be applied to the indicator
readings SYMBOLS: T = Top of Coupling R = Right side of Coupling B
= Bottom of Coupling L = Left side of Coupling TIR =Total Indicator
Reading Vo = Vertical Offset Ho = Horizontal Offset V1 = Distance
from the present to desired state of Mach B's projected CL at
Coupling "A" V2 = Distance from Coupling "B's" present to desired
state less V1 Note: V1 and V2 are only intermediate steps needed to
form a working Triangle for calculations. = Near Foot of Machine B
or the Nf Measured Point Nearest to the Coupling Ff = Far Foot of
Machine B or the Measured point farthest from the Coupling Lesson 5
Page 3 58. Machine alignment Reverse Alignment Method With Thermal
Growth D1 = Distance between the Indicator Planes, Plunger-to-
Plunger. = The distance from the Indicator D2 Plane of Machine "A"
to the Near Measured Point of Machine "B" (Nf) CL = Center Line CZ
= Center Zone, Center of the Linear Zone of Proximeter Graph Curve.
2.4 MEASURED DISTANCES In order to graph or mathematically compute
the correct adjustment needed to achieve the desired alignment, it
will be necessary to establish three (3) measurements. These
measurements are critical to the success of one move alignment and
must be accurate to within 1/16 inch. 1. We must know the distance
between the planes in which the dial indicator readings were taken
(Plunger to Plunger). This distance is referred to as D1. 2. It is
also necessary to know the distance from the indicator plane of
machine A to the near adjustment plane of machine B . This is the
distance between the indicator plane of Machine A to the near foot
(Nf) of Machine B referred to as D2. 3. The distance between the
indicator plane of A to the far adjustment plane is needed. This
distance is referred to as D3 and is the distance between the
indicator plane of Machine A to the far foot (Ff) of Machine B.
Lesson 5 Page 4 59. Machine alignment Reverse Alignment Method With
Thermal Growth Fig.1-3 2.5 ALIGNMENT MOVEMENTS The vertical and
horizontal adjustment necessary to move Machine B from PRESENT to
DESIRED relative position can be computed. The shim adjustment at
the near foot (Nf) and far foot (Ff) can be determined in the
vertical movement formula. The side to side movement at near foot
(Nf) and far foot (Ff) can be determined in the horizontal movement
formula. 1. Vertical Movement. V1 B3 B1 2 or (10) (36) 2 23 V2 B4
B2 2 V1or (20) (48) 2 (23) 11 N f V2 D2 D1 V1or 1112 8 (23) 40 At
near Foot of "B", Add 0.040 Inch Shims Ff V2 D3 D1 V1or 11 24 8
(23) 56 At Far Foot of "B", Add 0.0.056 Inch Shims Lesson 5 Page 5
60. Machine alignment Reverse Alignment Method With Thermal Growth
2. Horizontal Movement. V1 (R3 L3 ) (R1 L1) 2 or (15) (5) (24) (12)
2 16 V2 (R4 L4 ) (R2 L2 ) 2 V1or [(6) (14)][(22) (26)] 2 (16) 22 N
f V2 D2 D1 V1or 2212 8 (16) 17 At near Foot of "B", Move Right
0.017 0.040 Inch Ff V2 D3 D1 V1or 22 24 8 (16) 50 At near Foot of
"B", Move Right 0.017 0.050 Inch Note: Observe all algebraic signs.
If answer is plus, move machine B up or left. If answer is minus
move machine B down or right. Fig.1- 4 Lesson 5 Page 6 61. Sag
Machine alignment Reverse Alignment Method With Thermal Growth
Fig.1- 5 Instructions for using the alignment specifications and
worksheet. Each note in the discussion is indicated on the attached
example by a circled number. 3.0 DETERMINING AMOUNT OF INDICATOR
BAR SAG indicator bar sag can be determined by firmly affixing it
to a sag free shaft mandrel, usually 4 inch diameter or larger,
dependent on length. The mandrel may be supported between lathe
centers, mounted on knife edges, or held and rotated by hand. With
the indicator bar positioned on top of the mandrel, the sag of bar
will be down toward the mandrel. Set indicator face to read zero at
this position. By zeroing the indicator, you have errored the
indicator by the amount of the sag. Rotate the mandrel 180
(indicator at bottom position). The indicator bar will sag away
from the mandrel; hence the indicator reading will be twice the
actual bar sag. TIR 2 Lesson 5 Page 7 62. Machine alignment Reverse
Alignment Method With Thermal Growth Once the indicator bar sag is
determined, it should be permanently stamped on the bar. This true
sag must be accounted for when determining sweep readings. 4.0
CORRECTING BY THERMAL GROWTH FACTOR When machinery is operating the
moving parts cause friction that in turn creates heat buildup
causing the machinery to expand. This expansion in the machinery is
called Thermal Growth. The amount of movement can be predicted when
you know the machinery's material, temperature change, and the
distance between shims and shaft centerline. 4.1 CALCULATING
THERMAL MOVEMENT Fig.1-6 Growth = T x L x C Growth in mils T =
Change in F L = Inches, shim to shaft center line C = Growth factor
Example: T = 40 L = 14 C = 0.0063 T x L x C = Growth 40 x 13 x
0.0063 = 3.27 = 0.003 Lesson 5 Page 8 63. Machine alignment Reverse
Alignment Method With Thermal Growth Growth Factors: 0.0126 =
Aluminum 0.0100 = Bronze 0.0059 = Cast Iron 0.0074 = Stainless
0.0063 = Mld Steel 4.2 GRAPHING THERMAL MOVEMENT Most machinery
must be misaligned cold so that the shafts will be collinear during
normal operating conditions. Graphing the move above shows us that
the pump does not move (no change in temperature) and the motor
rises an estimated .003" (3 mils). Fig.1-7 Pump stays the same
Motor rises .004" at both feet Lesson 5 Page 9 64. Machine
Alignment Vertical Pump Alignment LESSON 6 LECTURE VERTICAL PUMP
ALIGNMENT DETAILED PROCEDURE BY CALCULATION Objectives The
objective of this module is to make students understand the basic
concept and procedure of vertical pump alignment. 1.0 IMPORTANT
FUNDAMENT POINTS FOR VERTICAL ALIGNMENT Please note down following
points to understand and perform vertical pump alignment. a. In
vertical pumps we will only add the shim to correct angular
misalignment and we will make correction of angular misalignment in
two planes. b. The angular correction is done with the help of
simple relation between distance from centre of bolt hole to centre
of opposite bolt hole of flange, coupling diameter, correction shim
required and angular reading (difference of gap between coupling
hubs top and bottom). c. You should go through the derivation of
angular correction formula. d. It should be noted that when we make
angular correction it will change the radial position. e. The
change of radial alignment or position can be calculated easily by
another relation which is between correction shim thickness, flange
diameter where shims are added, angular reading and distance
between shimming point to coupling hub face. Check the figure and
derivation. There is also example of solved problem. Remember we
select two planes for angular correction. 1.1 VERTICAL PUMP
ALIGNMENT AND EFFECT OF VERTICAL ANGULAR CORRECTION ON RADIAL
POSITION. See fig 1 Y is the distance between flange opposite bolts
centers. X is the shim required for angular correction . Lesson 6
Page 1 65. Machine Alignment Vertical Pump Alignment C is coupling
diameter change due to shim x added. b is distance from shimming
point to coupling hub face. R is the shift in radial
position(radial alignment) By geometry of triangles we can get the
simple relation as given below. See fig 1 A/C=X/Y X(angular
correction shim required)=A/C * Y R/b=X/Y R(radial position
shift)=X/Y * b For angular alignment Shim required = Angular
reading x Distance between opposite bolts of flange . Coupling
Diameter Radial alignment position change due to angular correction
. = Shim Added x distance between shimming point and coupling hub
face. Distance Between opposite bolts holes centers of flange Y X b
C A R Fig. 1-6 Lesson 6 Page 2 66. Machine Alignment Vertical Pump
Alignment 1.2 EFFECT OF ADDING SHIMS (FOR FACE CORRECTION) ON
RADIAL READINGS IN VERTICAL PUMPS See figure 2. Flange DD position
shifts to position DD and Shaft YA shifts to new position YA . B =
G . W DD B = G*W DD W = Distance from shimming point to coupling
hub G = correction shim thickness. DD = Distance between opposite
bolts holes centres of flange B = Change in radial position.
Point(A) shifts to Point (A) D G Shimming Distance YDD Shifts To DD
W YA Shifts To YA A B A D D Fig 2-6 Lesson 6 Page 3 67. +2 A +6 DD
= 22 Machine Alignment Vertical Pump Alignment SOLVED EXAMPLE E . 0
D +8 ANGULAR READING IS.D = 0.001 Coup Dia = 6 Distance Between
Flange and Coupling Hub = 20 DD 22 E FLANGE C D 6 20 20 A Fig3-6
Lesson 6 Page 4 68. Machine Alignment Vertical Pump Alignment
VERTICAL PUMP ALIGNMENT CALCULATION. Shim reqd at D = 4 x 22 =
14.65 thous or mils. 6 Shim reqd at E = 8 x 22 = 29.28 mils. 6 When
we put shim of 14.65 mils at D we will also need to put shim of
14.65/2 at E and E (which is 7.3 mils) so that there is no soft
footness or gap. When we put shim of 29 mils at E we will also need
to put shim of 29/2 mils shim at points D and D (which is 14.5
mils) So net result is: AT D = 14.65 + 29/2 = 14.65 + 14.5 = 29
mils AT D = 29/2 = 14.5 mils AT E = 295 + 14.5/2 = 36.3 mils AT E =
14.5/2 = 7.25 = 7 mils But if we remove shim of same size from all
four positions which are D, D, E, E there will be no effect or
change in alignment. So net shims reqd to be added at points D, D,
E, E are: AT D = 29 7 = 22 mils AT D = 14.5 7.2 = 7.3 = 7 mils AT E
= 36.3 7.2 = 29 mils AT E = 7.25 7.2 = 0 mils Lesson 6 Page 5 69.
Machine Alignment Vertical Pump Alignment DD 24 C 6 20 A Fig 4-6
Lesson 6 Page 6